The invention relates to rolling devices such as roller skis and in-line skates.
Roller skis are very short skis that have front and rear wheels and are used for training devices by skiers when snow is not available. They are also used by many athletes in other sports. Studies by exercise physiologists have shown that roller skis are one of the most effective methods of training for all endurance sports including running and cycling. In-line skates have small narrow wheels positioned one after the other, i.e., in line. In-line skates are used for recreation, for training ice skating in off season or for general aerobic conditioning. In the U.S. roller skis and in-line skates are typically used on roads or park paths. In Scandinavia and Central Europe, as well as in several places in North America, there are now specific roller ski and in-line skate tracks. Each year these forms of training and recreation are becoming more popular, resulting in the building of more tracks specifically designated for these activities.
A major problem with roller skis and in-line skates has been the inability to slow down or stop when going down hills. A few prior art roller skis have used frictional brakes rubbing against the tire or hub of the wheel. U.S. Pat. No. 4,898,403 describes the use of kinematic damping to provide the necessary resistance for optimal training and slowing roller skis on less steep hills, but did not provide variable (adjustable) resistance or quick stopping.